The TPL Dataflow Library (System.Threading.Tasks.Dataflow namespace) is not distributed with the .NET Framework 4.5. To install the System.Threading.Tasks.Dataflow namespace, open your project in Visual Studio 2012, choose Manage NuGet Packages from the Project menu, and search online for the Microsoft.Tpl.Dataflow package.

Provides a buffer for storing at most one element at time, overwriting each message with the next as it arrives. Messages are broadcast to all linked targets, all of which may consume a clone of the message.

Provides a dataflow block that joins across multiple dataflow sources, not necessarily of the same type, waiting for one item to arrive for each type before they’re all released together as a tuple consisting of one item per type.

Provides a dataflow block that joins across multiple dataflow sources, which are not necessarily of the same type, waiting for one item to arrive for each type before they’re all released together as a tuple that contains one item per type.